Author: Vincent Diepeveen
Date: 14:33:10 06/15/04
Go up one level in this thread
On June 15, 2004 at 16:50:02, Tony Werten wrote: >On June 15, 2004 at 13:17:57, Vincent Diepeveen wrote: > >>On June 14, 2004 at 19:20:57, Anthony Cozzie wrote: >> >>It has nothing to do with double nullmove not finding it. Instead double >>nullmove *does* find this. >> >>Only normal nullmove doesn't find it. >> >>It's of course like so many 'zugzwangs' another evaluation issue. >> >>Just be sure you evaluate qd2+ kxg4 qe3 b5 axb5 as more positive than some >>positions which start with gxh5. > >I don't think it's an evaluation issue. The difference in score is over 10 >pawns. I your program doesn't see that within 30 secs, it's either buggy or >pruning like crazy or blindly nullmoving. >Tony It is an evaluation issue. It is not a 10 pawn thing but a 0.1 pawn thing rather. Diep evaluates the position after qd2 kg4 qe3 b5 ab as black up 0.6xx And at 11 ply it evaluates black up after gxh5 as black up 0.8xx So nullmoving doesn't work then for black after you see the above line. Then you get a fail high with qd2 kg4 qe3 as a mainline. Now nullmove doesn't fail high for black because beta = infinite. So then you suddenly see the entire mainline without zugzwangs and get 10.xx as a score. In other words it's an evaluation issue of the position after qd2 kg4 qe3 b5 ab versus the root score that gxh5 gives back. That's all there is. > >> >>That's all. >> >>Diep finds it at 11 ply : >> >>00:00 22 22 0 (2) 1 (0,0) -0.471 g4xh5 Kg5xh5 >>00:00 266 266 0 (2) 2 (0,1) -0.471 g4xh5 Kg5xh5 >>00:00 835 835 0 (2) 3 (0,3) -0.061 g4xh5 Qh4-g4 Kg2-f1 g6xh5 Qd4xb6 Qg4xe4 Qb >>6xa5 Kg5-h6 >>00:00 147450 2949 0 (2) 4 (0,6) -0.061 g4xh5 Qh4-g4 Kg2-f1 g6xh5 Qd4xb6 Qg4xe4 Q >>b6xa5 Kg5-h6 >>00:00 147680 7384 0 (2) 5 (0,15) -0.061 g4xh5 Qh4-g4 Kg2-f1 g6xh5 Qd4xb6 Qg4xe4 >>Qb6xa5 Kg5-h6 >>00:00 180507 25271 0 (2) 6 (2,35) -0.133 g4xh5 Qh4-g4 Kg2-f1 Qg4-f4 Kf1-g1 g6xh5 >> Qd4xb6 Qf4-e5 >>00:00 192151 74939 0 (2) 7 (10,92) -0.139 g4xh5 Qh4-g4 Kg2-f1 Qg4-f4 Kf1-g1 Qf4- >>g3 Kg1-h1 g6xh5 Qd4xb6 Qg3-e5 >>00:01 229359 311929 0 (2) 8 (25,245) -0.080 g4xh5 Qh4-g4 Kg2-f2 Qg4-f4 Kf2-g1 Qf >>4-g3 Kg1-h1 >>00:02 248265 585907 0 (2) 9 (56,492) -0.547 g4xh5 Qh4-g4 Kg2-f2 Qg4-f4 Kf2-g1 g6 >>xh5 Qd4xb6 Qf4xe4 Qb6xa5 Kg5-g4 Qa5-c5 Qe4-b1 Kg1-h2 Qb1xb3 >>00:06 271934 1707751 0 (2) 10 (145,1157) -0.561 g4xh5 Qh4-g4 Kg2-f2 Qg4-f4 Kf2-g >>1 g6xh5 Qd4xb6 Qf4xe4 Qb6xa5 Kg5-g4 Qa5-c5 Qe4-e1 Kg1-g2 Qe1-g3 Kg2-h1 Qg3-h3 Kh >>1-g1 Qh3xb3 >>00:18 283545 5205900 0 (2) 11 (368,2660) -0.836 g4xh5 Qh4-g4 Kg2-h2 Qg4xh5 Kh2-g >>3 Qh5-g4 Kg3-f2 Qg4-e6 Qd4-e3 Kg5-f6 Qe3-d4 Kf6-f7 Qd4-e3 Kf7-g7 >>++ d4-d2 procnr=0 terug=-561 org=[-836;-835] newwindow=[-836;520000] >>00:34 293568 10013609 0 (2) 11 (565,3928) 11.263 Qd4-d2 Kg5xg4 Qd2-e3 b6-b5 a4xb >>5 a5-a4 b5-b6 a4xb3 b6-b7 b3-b2 b7-b8Q Qh4-h1 Kg2xh1 b2-b1Q Kh1-g2 >>00:39 297525 11814753 0 (2) 12 (592,4329) 11.263 Qd4-d2 Kg5xg4 Qd2-e3 b6-b5 a4xb >>5 a5-a4 b5-b6 a4xb3 b6-b7 b3-b2 b7-b8Q Qh4-h1 Kg2xh1 b2-b1Q Kh1-g2 >>01:39 304837 30212461 0 (2) 13 (1154,8778) 11.263 Qd4-d2 Kg5xg4 Qd2-e3 b6-b5 a4x >>b5 a5-a4 b5-b6 a4xb3 b6-b7 b3-b2 b7-b8Q Qh4-h1 Kg2xh1 b2-b1Q Kh1-g2 >>02:37 312094 49042542 0 (2) 14 (1324,10654) 11.263 Qd4-d2 Kg5xg4 Qd2-e3 b6-b5 a4 >>xb5 a5-a4 b5-b6 a4xb3 b6-b7 b3-b2 b7-b8Q Qh4-h1 Kg2xh1 b2-b1Q Kh1-h2 Qb1-c2 Qe3- >>f2 >> >>>On June 14, 2004 at 16:31:17, Jaime Benito de Valle Ruiz wrote: >>> >>>>[d]8/8/1p4p1/p5kp/Pp1QP1Pq/1P6/6K1/8 w - - 0 62 >>>> >>>>White moves and wins! >>>>Can your engine find the right answer and give the proper "crushing" score >>>>(around 9 pawns!) along with a proper PV? How long does it take? >>>>Mine doesn't find anything after a long long time (over an hour), but with >>>>null-move disabled, it takes only a few seconds to show the full PV. >>>>(Some engines find the right answer, but with a small score, an absurd PV, and >>>>they change their mind some plies later) >>>> >>>>In this position the black king is in a very delicate position: After a couple >>>>of moves, if the black queen moves, white checkmates inmediately, so both kings >>>>and queens must remain still while pawns play on their own. >>>> >>>>Any good suggestion to avoid this problem with null-move? >>>> >>>>Regards, >>>> >>>> Jaime >>> >>>Zappa doesn't get it either (gxh5 @ 15 ply after 1 minute). Zappa relies on >>>double nullmove for zugzwang avoidance. This works find for positions with 1 >>>zugzwang, but in this position black gets hit with about 10 of them :) >>> >>>anthony
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.